https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106513
--- Comment #2 from Krister Walfridsson <kristerw at gcc dot gnu.org> --- (In reply to Andreas Schwab from comment #1) > This subexpression has undefined behaviour: (((int64_t) 0xff) << 56). I thought that was allowed in GCC as the manual says (https://gcc.gnu.org/onlinedocs/gcc-12.1.0/gcc/Integers-implementation.html#Integers-implementation) "As an extension to the C language, GCC does not use the latitude given in C99 and C11 only to treat certain aspects of signed ‘<<’ as undefined." If not, what behavior does the manual refer to?
